1. Field of the Invention
The present invention relates to a method of and an apparatus for processing polished cereal such as polished rice to obtain no-bran cereal which require no washing before cooking, and in particular to a method and an apparatus capable of removing bran stuck on a surface of the polished cereal without imparting any damage on the surface.
2. Description of the Related Art
The no-bran rice which requires no wash before cooking is going to be brought into the market. There are known a method in which polished rice processed by a polishing machine is subjected to polishing in water for a minute time and then dehydrated to be dried, and a method in which the polished rice is polished by a grinding blush or a rubber roll, and a method adhesive material such as amyloid, sugar and saccharide is added to the polished rice and then removed. In these methods, an aleurone layer remaining in grooves or concaves on the surface of the polished rice is removed from the rice by the waterpolishing, the polishing and the adhesive material, to obtain the no bran rice.
In Japanese Patent Publication No.11-137191, there is disclosed a method in which grained rice in a range of 10 through 50 mesh is mixed to the polished rice at a rate of 100 to 10-200 by weight, and stirred to polish the polished rice and remove the bran remaining on the surface of the polished rice, and then the polished rice is separated from the grained rice. Since the bran remaining on the surface of the polished rice is removed with the above methods, washing and polishing of rice before boiling can be omitted and thus preventing nutrient from losing by washing and also preventing contamination of river by the washing water. However, a relative high pressure is required in removing the bran from the polished rice by the grained rice since the mixture of the polished rice and the grained rice is performed without adding any water to the polished rice. Therefore, a mixing machine with an agitator, an epithelium of endosperm on the surface of the rice may be cut by the high pressure and receive damages on the surface. In winter season, more high pressure is required to effectively remove the bran since the surface of the polished rice is hardened.
On the other hand, in polishing brown rice, a temperature of the brown rice is increased by friction heat before and after the polishing process and moisture of the polished rice is decreased. In manufacturing the no-bran rice by the above methods using the polished rice with low moisture, it is certain that the moisture in the processed no-bran rice is decreased to 15% or lower in weight, to lower a taste of the boiled rice.
An object of the present invention is to provide a no-bran cereal manufacturing method and an apparatus therefor capable of removing bran stuck on a surface of each grain of the cereal without imparting any damage on the surface and also improving taste of the cereal by maintaining the moisture of the cereal.
A method of manufacturing no-bran cereal of the present invention comprises the steps of: adding moisture to polished cereal; mixing and stirring granular material with the moistened polished cereal so as to remove bran stuck on a surface each grain of the polished cereal; and separating the polished cereal from the granular material.
The cereal may be rice, wheat barley corn. As the granular material, grinded rice, pre-gelatinized grinded rice, grinded wheat, grinded barleycorn, grinded millet, grinded buckwheat, grinded kaoliang and pearl tapioca can be preferably used.
The granular material may be heated before the step of mixing and stirring granular material with the moistened polished cereal. In this case, the granular material is heated to a temperature not lower than 60xc2x0 C., preferably in a range between 60xc2x0 C. and 80xc2x0 C.
The polished cereal may be obtained by polishing hulled cereal with an conventional polishing device or by processing the hulled cereal by passing the hulled cereal through a pair of rollers coated by elastic material by a plurality of times.
The step of adding moisture to the polished cereal may include spraying the polished cereal with water and stirring the polished cereal.
After performing the step of adding moisture to the polished cereal, the steps of mixing/stirring granular material with the moistened polished cereal and separating the polished cereal from the granular material may be repeatedly performed.
After performing the step of separating the polished cereal from the granular material, the polished cereal may be subjected to wet-polishing.
The step of adding moisture to the polished cereal may be performed immediately after finishing the polishing of the hulled cereal.
In order to carrying out the above method, an apparatus for manufacturing no-bran cereal is provided according to the present invention. The apparatus may comprise: moisture adding means for adding moisture to polished cereal; mixing/stirring means for mixing and stirring granular material with the moistened polished cereal to remove bran stuck on a surface of each grain of the polished cereal; and separating means for separating the polished cereal from the granular material. The apparatus may further comprise heating means for heating the granular material before being fed to the mixing/stirring means, and may further comprise a polishing means for polishing hulled cereal to obtain the polished cereal. The polishing means may comprise a pair of rollers coated by elastic material through which the hulled cereal is passed by a plurality of times.
The moisture adding means may include a sprayer for spraying the polished cereal with water and a stirrer for stirring the polished cereal. The apparatus may further comprise an additional mixing/stirring means for mixing and stirring the polished cereal separated by said separating means and granular material; and an additional separating means for separating the polished rice from the granular material. The apparatus may further comprise a wet-polishing means for wet-polishing the polished cereal separated by said separating means.